U.S. patent application number 12/800455 was filed with the patent office on 2011-11-17 for systems and methods for enhanced recovery of hydrocarbonaceous fluids.
Invention is credited to Paul Grimes.
Application Number | 20110277992 12/800455 |
Document ID | / |
Family ID | 44910726 |
Filed Date | 2011-11-17 |
United States Patent
Application |
20110277992 |
Kind Code |
A1 |
Grimes; Paul |
November 17, 2011 |
Systems and methods for enhanced recovery of hydrocarbonaceous
fluids
Abstract
A method for enhanced recovery of hydrocarbonaceous fluids, the
method including the steps of connecting each of a plurality of
wellbores together in fluid communication with a machined flow
path, providing a surface fluid to the flow path, and generating an
electrical field within the flow path to cause an electrochemical
reaction to produce a gas from the fluid, such that the gas mixes
with hydrocarbonaceous fluids and increases pressure within at
least one of the plurality of wellbores, the flow path, and
combinations thereof, thereby enhancing recovery of the
hydrocarbonaceous fluid.
Inventors: |
Grimes; Paul; (Houston,
TX) |
Family ID: |
44910726 |
Appl. No.: |
12/800455 |
Filed: |
May 14, 2010 |
Current U.S.
Class: |
166/248 ;
166/268 |
Current CPC
Class: |
E21B 43/2401 20130101;
E21B 43/30 20130101 |
Class at
Publication: |
166/248 ;
166/268 |
International
Class: |
E21B 43/16 20060101
E21B043/16; E21B 43/18 20060101 E21B043/18 |
Claims
1. A system for enhanced recovery of hydrocarbonaceous fluids, the
system comprising: a first wellbore comprising a first electrode
disposed therein; a second wellbore comprising a second electrode
disposed therein; a machined flow path disposed in fluid
communication with the first wellbore and the second wellbore; a
solution disposed within the machined flow path, wherein the first
electrode and the second electrode extend at least partially into
the solution; and a power source operatively connected to the first
electrode and the second electrode, and configured to produce an
electrical field therebetween, wherein the electrical field causes
an electrochemical reaction within the solution to create a gas for
permeating hydrocarbonaceous fluids and for increasing pressure
within at least one of the first wellbore, the second wellbore, the
machined flow path, and combinations thereof, thereby enhancing
recovery of the hydrocarbonaceous fluids.
2. The system of claim 1, wherein the power source is configured to
provide alternating current to the first electrode and the second
electrode.
3. The system of claim 1, further comprising at least one pump for
providing the solution to the machined flow path.
4. The system of claim 1, wherein the solution comprises brine, and
the gas comprises hydrogen.
5. The system of claim 1, wherein the machined flow path comprises
a horizontally drilled conduit.
6. The system of claim 1, further comprising a third wellbore
comprising a third electrode disposed therein, wherein the machined
flow path further provides fluid communication between the third
wellbore and at least one of the first wellbore and the second
wellbore.
7. The system of claim 6, the system further comprising a producing
formation and a non-producing formation external of the producing
formation, wherein the hydrocarbonaceous fluids reside in the
producing formation, and wherein the machined flow path resides in
the non-producing formation.
8. The system of claim 6, wherein the machined flow path further
provides triangulated fluid communication between the first
wellbore, the second wellbore, and the third wellbore.
9. The system of claim 7, wherein the machined flow path is
disposed substantially adjacent to a producing formation comprising
hydrocarbonaceous fluids.
10. The system of claim 1, the system further comprising a
producing formation and a non-producing formation external of the
producing formation, wherein the hydrocarbonaceous fluids reside in
the producing formation, and wherein the machined flow path resides
in the non-producing formation.
11. A method for enhanced recovery of hydrocarbonaceous fluids, the
method comprising: connecting each of a plurality of wellbores
together in fluid communication with a machined flow path;
providing a surface fluid to the flow path; and generating an
electrical field within the flow path, thereby causing an
electrochemical reaction to produce a gas from the fluid, wherein
the gas mixes with hydrocarbonaceous fluids and increases pressure
within at least one of the plurality of wellbores, the flow path,
and combinations thereof, thereby enhancing recovery of the
hydrocarbonaceous fluid.
12. The method of claim 11, wherein the step of generating the
electrical field comprises providing alternating current to the
surface fluid.
13. The method of claim 12, wherein the alternating current is
produced from a renewable energy source.
14. The method of claim 11, the method further comprising the steps
of measuring the enhanced recovery, and optimizing the enhanced
recovery by changing the electrical field through select adjustment
of at least on of a voltage, a frequency, and combinations
thereof.
15. The method of claim 11, wherein the hydrocarbonaceous fluids
reside in a producing formation, and wherein the machined flow path
resides in a non-producing formation adjacent to the producing
formation.
16. The method of claim 11, wherein the step of connecting each of
the plurality of wellbores comprises drilling a conduit to place
each of the plurality of wellbores in fluid communication.
17. The method of claim 16, wherein the step of drilling the
conduit comprises drilling a substantially horizontal conduit.
18. The method of claim 11, wherein the step of connecting each of
the plurality of wellbores comprises providing a triangulated
pattern of fluid communication between three wellbores.
19. The method of claim 11, wherein the step of generating the
electrical field comprises disposing a plurality of electrodes into
the fluid, and wherein the fluid conducts the electrical field
between the plurality of electrodes.
20. The method of claim 11, wherein the step of providing the fluid
to the flow path comprises providing brine to the flow path, and
wherein the electrochemical reaction produces hydrogen gas as a
result of applying the electrical field to the brine.
21. A method for tertiary recovery of hydrocarbonaceous fluids, the
method comprising: creating at least part of an artificial
subterranean formation external to a natural producing formation;
reacting a fluid disposed in the artificial formation to form a
gas; permeating the gas into the natural producing formation,
wherein the permeated gas in the natural producing formation
increases pressure within the natural producing formation; and
mixing the gas with hydrocarbonaceous fluids disposed in the
natural producing formation, thereby enhancing recovery of the
hydrocarbonaceous fluid.
22. The method of claim 21, wherein the artificial subterranean
formation comprises three wellbores in fluid communication thereby
forming a triangulated wellbore configuration, and wherein each of
the three wellbores comprise electrodes disposed therein to provide
polarization to the fluid.
23. The method of claim 22, wherein the artificial formation is
entirely external of the natural producing formation.
24. The method of claim 21, wherein the artificial subterranean
formation comprises a plurality of wellbores, and wherein at least
two of the plurality of wellbores are in fluid communication by a
horizontally drilled conduit formed substantially underneath the
natural producing formation.
25. The method of claim 21, wherein the artificial subterranean
formation comprises a plurality of wellbores, and wherein at least
two of the plurality of wellbores are in fluid communication by a
horizontally drilled conduit formed substantially within the
natural producing formation.
26. The method of claim 21, wherein a renewable energy source
produces a current usable to form an electric field within the
artificial subterranean formation, and wherein the fluid reacts as
a result of an electrolysis process created by the electric
field.
27. The method of claim 21, wherein the producing formation is
configured for at least one of gas injection, water flooding, and
combinations thereof.
28. The method of claim 21, wherein the fluid comprises brine
solution, and the gas comprises hydrogen.
29. The method of claim 21, wherein the artificial formation is
entirely external of the natural producing formation.
Description
BACKGROUND OF THE DISCLOSURE
[0001] 1. Field of the Disclosure
[0002] Embodiments disclosed herein generally relate to systems and
methods that enhance the recovery of hydrocarbonaceous fluids.
Specific embodiments relate to systems and methods to stimulate a
producing formation by using a gas generated from an
electrochemical reaction. Other embodiments relate to the use of AC
electrolysis in a machined formation adjacent to and/or within a
producing formation to generate a gas that permeates into
hydrocarbonaceous fluids disposed in the producing formation.
[0003] 2. Description of the Related Art
[0004] Large deposits of hydrocarbonaceous fluids, such as crude
oil, are known to exist in subterranean formations throughout the
world. In the past, these fluids were recovered from the formations
until the natural energy (e.g., pressure) of the formation expired,
at which point the formation was typically abandoned. This primary
recovery typically produced as little as 15%-25% of the
hydrocarbonaceous fluids within the formation, with the large
majority of hydrocarbons left unrecovered because the economic cost
of continued production exceeded the value of the quantity of
hydrocarbonaceous fluids recovered. As the value of
hydrocarbonaceous fluids increased, secondary recovery processes
became economically justifiable for use to increase production from
formations.
[0005] Secondary recovery may include, for example, a pumping
operation that draws previously unrecoverable fluids to the
surface. However, these processes vary greatly, as processes that
enable successful recovery from one or more formations may not be
economical and/or successful when used in conjunction with other
formations. In addition, the capabilities of secondary recovery
methods are limited. For example, formations that contain
hydrocarbonaceous fluids with a low specific gravity, and/or high
viscosity, and possess little or no natural energy may be
unaffected by secondary recovery. In the absence of formation
pressure, even fluids of average viscosity and specific gravity are
difficult to produce through secondary recovery methods without
addition of external energy to the formation.
[0006] As such, a great deal of attention has recently been given
to various methods of tertiary recovery. Logically, an abundance of
tertiary recovery processes consider energy-based techniques that
increase the temperature (i.e., reduce viscosity) and/or the
pressure of the producing formation, thereby increasing
flowabilitiy. For example, "fire flooding" employs the technique of
burning oil "in situ" or within the formation, thereby heating the
formation and pressurizing the formation with resultant hot
combustion gases.
[0007] Gas injection is another example of a tertiary process.
Under injection pressures, CO.sub.2 gas may be solvent with
hydrocarbonaceous fluids, which increases the actual volume of the
fluids and also reduces specific gravity and viscosity. Thus, the
solvency of the injected gas provides increased formation pressure
and less viscous hydrocarbonaceous fluids. CO.sub.2 injection into
the formation also causes the hydrocarbonaceous fluids to "break
out" of the formation matrix, and thereby further promotes
increased production. Nevertheless, many tertiary processes, such
as gas injection, require extensive and/or cost-prohibitive surface
equipment and operations, and may also cause damage to the
producing formation that hinders or terminates future production
ability.
[0008] Some economical tertiary processes include introducing an
electric current into the producing formation to cause exothermal
heating of the surrounding formation, which lowers the viscosity of
hydrocarbonaceous fluids and stimulates flow. Typically, electrodes
are connected to an electrical power source and are positioned at
spaced apart points within the producing formation, whereby single
electrodes are usually disposed in a corresponding wellbore that
penetrates into the producing formation. When current passes
between the electrodes and the formation, high resistance of the
formation causes power to dissipate, which results in a power loss
that heats the producing formation and hydrocarbonaceous fluids.
However, this process is generally limited to the immediate area
involved in the heating process.
[0009] There is a need for economical and readily useable enhanced
recovery systems and methods that beneficially use an
electrochemical reaction, but do not require constituent elements
within the producing formation. There is a need for an
electrochemical reaction that may generate a gas that permeates
and/or mixes with formation fluids, whereby the pressure of the
producing formation may be increased and/or viscosity of
hydrocarbonaceous fluids reduced, thereby increasing flowability.
There is also a need to monitor and optimize systems and methods
that use an electrochemical reaction to enhance recovery of
hydrocarbonaceous fluids. Other needs addressed by embodiments
disclosed herein include the ability to convert clean renewable
energy into .about.100% usable energy.
SUMMARY OF THE DISCLOSURE
[0010] Embodiments of the present disclosure relate, generally, to
systems and methods for enhanced recovery of hydrocarbonaceous
fluids. Electrodes may be provided into two or more wellbores. The
wellbores may include preexisting producing and/or abandoned
wellbores, naturally occurring features, or additional wellbores
that may be drilled, machined, or otherwise formed to facilitate
performance of the enhanced recovery process described herein.
[0011] The wellbores may then be placed in fluid communication
through the creation of a machined flow path therebetween. For
example, horizontal drilling or similar methods for forming flow
paths may be used to connect two or more wellbores. In an
embodiment of the disclosure, three wellbores having electrodes
therein may each be provided in fluid communication with one
another. It should be understood that any configuration of
wellbores and electrodes may be used, such that at least two
wellbores having electrodes therein are provided in fluid
communication.
[0012] A solution, such as brine or a similar generally conductive
fluid, is pumped or otherwise provided within the machined flow
path, such that the electrodes extend at least partially therein. A
power source operatively connected to the electrodes is then
actuated to produce an electrical field therebetween. In an
embodiment of the disclosure, generation of the electrical field
may include application of alternating current to the solution.
[0013] The electrical field causes an electrochemical reaction
within the solution to create a gas that may solvently mix with in
situ hydrocarbonaceous fluids, thereby increasing pressure within
the formation and/or decreasing the viscosity of the
hydrocarbonaceous fluids. As one example, brine may be provided
into the machined flowpath, and the electrochemical reaction may
form hydrogen gas. The formed gas may freely pass into adjacent
formations containing hydrocarbonaceous fluids, mix with
hydrocarbonaceous fluids to reduce the viscosity thereof, and
increase pressure within the machined flowpath, wellbores, and/or
adjacent formations.
[0014] An alternate embodiment may include creating an artificial
subterranean formation at least partially underneath a producing
and/or abandoned formation containing hydrocarbonaceous fluids. A
fluid, such as brine, disposed in the artificial formation may be
reacted to form a gas (i.e., hydrogen), which may permeate into the
producing formation to increase the pressure therein and/or
decrease viscosity of the hydrocarbonaceous fluids.
[0015] Embodiments disclosed herein may be used to increase a
formation pressure, or otherwise alter flow characteristics of
fluids in the formation. This may include, for example, a tertiary
recovery process that establishes an electrical current flow within
a formation via one or more electrodes that extend into the
formation. The current flow may generate a zone of electrochemical
activity in the formation that causes an electrochemical reaction
with solutions disposed in the formation, thereby generating
volumes of free gases to increase the formation pressure.
[0016] The electrochemical activity further enhances flow
characteristics of formation fluids by lowering the viscosity of
the fluids. The increased formation pressure acts to drive the
hydrocarbonaceous fluids into a producing wellbore. The process may
also release fluids from the earth formation matrix that are within
the zone of electrochemical activity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIGS. 1A and 1B depict multiple views of a various
embodiments of a system for enhanced recovery of hydrocarbonaceous
fluids, useable within the scope of the present disclosure.
[0018] FIG. 1C shows a cross-sectional view of a conduit useable in
one of the systems of FIGS. 1A and 1B, within the scope of the
present disclosure.
[0019] FIG. 2 depicts a side view of an embodiment of a system for
enhanced recovery of a producing formation separate from a
non-producing formation, useable within the scope of the present
disclosure.
[0020] FIG. 3 depicts a side view of an alternate embodiment of a
system for enhanced recovery of hydrocarbonaceous fluids, useable
within the scope of the present disclosure.
[0021] FIGS. 4A, 4B, 4C, 4D, 4E, and 4F depict multiple partial
downward sectional views of various embodied arrangements of
systems useable to enhance recovery of hydrocarbonaceous fluids, in
accordance with the scope of the present disclosure.
[0022] FIGS. 5A and 5B depict flow charts illustrating embodiments
of methods for enhanced recovery of hydrocarbonaceous fluids,
useable within the scope of the present disclosure.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] Embodiments of the present disclosure will now be described
in detail with reference to the accompanying Figures, which may
include like elements in various Figures denoted by like reference
numerals for consistency. The detailed description may also set
forth numerous specific details in order to provide a more thorough
understanding of the claimed subject matter. However, it should be
apparent to one of ordinary skill in the art that the embodiments
described may be practiced without these specific details. In other
instances, well-known features have not been described in detail to
avoid unnecessarily complicating the description.
[0024] In addition, directional terms, such as "above," "below,"
"upper," "lower," etc., are used for convenience in referring to
the accompanying drawings. In general, "above," "upper," "upward,"
and similar terms refer to a direction toward the earth's surface
from below the surface along a wellbore, and "below," "lower,"
"downward," and similar terms refer to a direction away from the
surface along the wellbore (i.e., into the wellbore), but is meant
for illustrative purposes only, and the terms are not meant to
limit the disclosure.
[0025] Referring now to FIGS. 1A, 1B, and 1C, multiple side views
of various embodiments of a system 100 for enhanced recovery of
hydrocarbonaceous fluids according to the present disclosure, is
shown. FIG. 1A shows the system 100 may include features and
components readily recognized by one of skill in the art, such as a
surface production facility 102 that produces hydrocarbonaceous
fluids 130 from a producing formation 110 by way of a wellbore 108.
The producing formation 110 may be surrounded by various
non-producing formations, such as overburden 114, bed rock 116,
and/or other earthen material 118.
[0026] A producing formation may be a formation that produces
appreciable amounts of hydrocarbonaceous fluids as a result of
primary, secondary, and/or tertiary recovery processes. An
appreciable amount of produced fluid may be, for example, one or
more barrels a day. A non-producing formation may be a formation
incapable of producing appreciable amounts of hydrocarbonaceous
fluids from primary, secondary, and/or tertiary recovery means. An
artificial (e.g., man-made, machined, drilled, etc.) formation may
advantageously be formed in the producing formation, the
non-producing formation, or combinations thereof.
[0027] For a formation to be productive, a pressure differential
must exist between the producing formation and the wellbore. Energy
for the pressure differential may be supplied naturally in the form
of gas, either free or in solution, evolved under a reduction in
pressure. Where the natural energy forces within the producing
formation are insufficient to overcome any retardant forces within
the formation, external energy must be added.
[0028] Thus, to enhance the recovery of the producing formation
110, an artificial formation 112 may be formed within (e.g., in the
vicinity of, as part of, etc.) the producing formation 110, which
may include, for example, a plurality of wellbores drilled therein.
In one embodiment, the artificial formation 112 may include a first
wellbore 104 in fluid communication with a second wellbore 106,
with a conduit 128 formed therebetween.
[0029] Wellbores 104, 106 and conduit 128 may be formed with
conventional drilling methods, such that the wellbores 104, 106 and
conduit 128 may be pressurized (including use of wellheads 122,
etc.), cased, cemented, perforated, etc., as would be understood to
one of skill in the art. In one embodiment, the conduit 128 may be
a substantially horizontally drilled wellbore. It should be
understood that in select embodiments, at least part of the
artificial formation 112 may be left uncased, uncemented, or
otherwise unmodified. For example, the conduit 128 may be drilled
through stable strata of the producing formation 110, such that
casing and/or cementing is not required.
[0030] In one embodiment, the wellbores 104, 106 and/or the conduit
128 may be at least partially disposed within or through the
producing formation 110, such that the wellbores 104, 106 and/or
conduit 128 are independently or simultaneously useable for
production of hydrocarbonaceous fluids 130. The artificial
formation 112 may be formed in the presence of pre-existing aqueous
solutions, such as saltwater, brine, etc. Alternatively, one or
more pumps 120 may be configured to convey a surface solution from
a source (not shown) to the artificial formation 112. The source
may include, for example, a storage tank at the surface or an
underground reservoir in communication with the pump.
[0031] The artificial formation 112, including any of the formation
112 components, such as conduit 128, may be formed in any portion
of the producing formation 110. Although FIG. 1A illustrates the
conduit 128 near the bottom of the producing formation 110, the
conduit 128 may be formed through a middle region, or through an
upper region (near the overburden 114 or the surface), such that
the location of where the conduit 128 is formed is not meant to be
limited to any specific location. FIG. 1B illustrates by way of
example the conduit 128 may be disposed in a general middle region
of the producing formation 110.
[0032] The producing formation 110 may be configured with a fresh
water flood or a gas injection process (e.g., carbon dioxide
injection), such that embodiments disclosed herein may readily
provide for the conversion of these processes to that of a
saltwater flood (or flood with other comparable electrolyte). The
saltwater flood may be accomplished to provide an electrolytic path
formed within the producing formation 110.
[0033] The wellbores 104, 106 may each have an electrode 132
disposed therein. As illustrated, the electrodes 132 may be located
near the bottom of the wellbores 104, 106, such that the electrodes
132 may extend at least partially into the solution 138. Although
FIGS. 1A and 1B illustrate two electrodes 132, it should be
understood that any number and configuration of electrodes 132
within any number or configuration of wellbores may be provided in
contact with the solution 138.
[0034] Any of the electrodes 132 may be made of electrically
conducting materials, such as, for example, aluminum or stainless
steel. However, other materials are also possible, such as graphite
or other semi-conductive material. As an example, the electrodes
may be any type of electrode known in the industry, such as the
electrode(s) described in either of U.S. Pat. Nos. 4,084,639 and
4,199,025 incorporated by reference herein in entirety. The
electrodes 132 may be, for example, metallic electrodes that are
long enough so that the lower ends of each may be immersed in the
solution 138. The upper ends of the electrodes 132 may be connected
by suitable leads (not shown) to an electrical power source
124.
[0035] The electrodes 132 may be disposed within the wellbores 104,
106 (and any solution 138 present in the wellbores) in any fashion.
For example, the electrodes 132 may be coupled to the end of a tube
string 133 or similar elongate member. The tube string 133 may
include various components, such as downhole tools, sliding
sleeves, conduits, connectors, etc. The tube string 133 may include
portions that are configured with electrically non-conducting
material, such as fiberglass, plastic, or other generally
non-conductive materials.
[0036] Hydrocarbonaceous fluids are generally poor conductors,
while an electrolyte, such as brine, is a good conductor. Since an
electric current will follow the path of least resistance, current
applied to the electrodes 132 will flow directly through the
solution 138 that is between the electrodes 132. The flow of
current may tend to heat the solution 138 in accordance with the
amount of solution 138 disposed therebetween, as well as the
magnitude of current being applied to the electrodes 132. The
heated solution may function as a heater with respect to the fluids
130 within the producing formation 110, whereby the viscosity of
the fluids 130 may be decreased, and the flow characteristics of
the fluids 130 in the formation 110 may be enhanced.
[0037] The electrodes 132 may be operatively connected with a power
source 124, which may be located at the surface or another location
in electrical communication with the electrodes 132. The power
source 124 may be used to create an electric field via an electric
circuit created by the power source 124, electrodes 132, and
solution 138, as described below. The power source 124 may be of
appropriate size and capacity in order to generate electric current
that may be conducted into the wellbores 104, 106, and into the
solution 138. Components connected between the power source, the
wellbores, the electrodes, etc., may be fully insulated from any of
the formation(s) in order to isolate the electrical current
path.
[0038] In one embodiment, the power source 124 may be any
conventional power source, such as a battery or steam/furnace
turbine-generator. In another embodiment, the power source 124 may
be a non-conventional power source, such as a renewable (i.e.,
green, clean, etc.) energy source. For example, there may be one or
more wind turbines that together may collectively form a wind farm
(not shown).
[0039] As known to one of ordinary skill in the art, a wind farm
may be a group of wind turbines in the same approximate location
that may be used for production of electric power. Individual
turbines may be interconnected with a voltage power collection
system, whereby electrical current that is produced by the turbines
may be transferred from the wind farm (via the power system) to the
electrodes 132, and into the solution 138. Thus, with a renewable
source, "green" energy is used, thereby eliminating the need to
obtain power from a conventional source (e.g., burning fossil
fuels). Furthermore, the ability to store and/or covert the green
energy into formation energy (i.e., increased formation pressure
and/or decreased viscosity) is advantageous compared to other
renewable energy processes that lose energy by inefficient
mechanical processes and/or transfer of energy to an energy
grid.
[0040] In some embodiments, any of the wellbores may be formed with
perforations (not shown), which may be present in the casing and/or
the artificial formation 112. The perforations may allow injection
of brine or other fluids from the surface into the artificial
formation 112. As such, the electrodes 132 may also have
perforations disposed therein. Accordingly, fluid injection may
occur by the conveyance of pressurized fluid through the tube
string 133, out the electrode perforations, and into the artificial
formation 112.
[0041] In some embodiments, depending on the construction of
conduit 128, the wellbores 104, 106 may allow fluids 130 from the
producing formation 110 to enter the wellbores and make contact
with electrodes 132. Upon application of the electrical current
from the power source 124 to the electrodes, an electric current
may be passed between the electrodes 132, and into the producing
formation 110.
[0042] The action of the electrical current passing through the
circuit formed by the electrodes 132, the power source 124, and the
solution 138 may heat the formation(s) 110 and/or 112 as a result
of the resistive properties of solution 138 and formation(s) 110
and/or 112. In addition, the electrochemical reactions may provide
increased internal pressure within the formation 110 to thereby
drive hydrocarbonaceous fluids 130 into a producing wellbore 108.
The electrochemical reaction may, for example, increase the
formation pressure as much as 300 psi over a large area.
[0043] The electrochemical action within the formation(s) may
produce at least the following phenomena: [0044] i) reduction in
the viscosity and specific gravity of the hydrocarbonaceous fluids
in the formation, thereby enhancing the flow characteristics of the
fluids; [0045] ii) generation of large volumes of free gas in the
formation due to electrochemical action with the solution; iii)
release of the hydrocarbonaceous fluids from the earth formation
matrix; and [0046] iv) production of heat within the formation
matrix in the area traversed by the current.
[0047] As shown by FIG. 1C, pressure within the wellbore(s) may be
sufficient enough to disperse solution 138 (and/or gas formed by
electrolysis) out into the producing formation 110. In one
embodiment, the solution 138 may disperse outwardly from the
artificial formation 112 in any direction. This may result, in one
example, because the pressure within the producing formation 110 is
insufficient to drive fluids 130 into the artificial formation 112.
Conversely, pressure within the artificial formation 112, as a
result of increased pressure, such as from pump 120, may cause
fluids within the artificial formation 112 to enter the producing
formation 110. The dispersal of fluid from the conduit 128 may be,
for example, in any outward direction from the conduit 128,
including 360-degree radial direction.
[0048] The ability to drive solution 138 into the producing
formation 110 helps broaden the area of where the electrolysis
process may occur. Thus, the electrochemical reaction may occur
within the formation 110 in an area that is much greater than the
area defined by the conduit 128. The extra pressure of the solution
138 (via the pressurization of the artificial formation 112) may
also provide additional pressure to the formation 110. This may
create a synergistic effect that helps further enhance the recovery
of the hydrocarbonaceous fluids 130 because the extra pressure
facilitates the movement of the fluids 130 toward the wellbore
108.
[0049] Referring now to FIG. 2, an embodiment of a system for
enhanced recovery of a producing formation separate from a
non-producing formation according to embodiments of the present
disclosure, is shown. System 200, which may be of a similar
construction and/or configuration as the system of FIG. 1, may
include a surface production facility 202 that produces
hydrocarbonaceous fluids 230 from a producing formation 210 by way
of a wellbore 208. The producing formation 210 may be surrounded by
one or more non-producing formations, such as overburden 214, bed
rock 216, and/or other earthen material 218.
[0050] To enhance the recovery of the producing formation 210, a
non-producing artificial formation 212 may be created adjacent
(e.g., in the vicinity of, next to, separate from, etc.) and
external to the producing formation 210. The artificial formation
212 may include, for example, a plurality of wellbores drilled
therein. Thus, in one embodiment, the artificial formation 212 may
include a first wellbore 204 in fluid communication with a second
wellbore 206, with a conduit 228 formed therebetween.
[0051] In some embodiments, the artificial formation 212 may be
formed in the presence of pre-existing aqueous solutions, or there
may be one or more prime movers (e.g., a pump) 220 configured to
convey a surface solution from a source (not shown) to the
artificial formation 212. Thus, the wellbores 204, 206 and/or the
conduit 228 may have an aqueous solution 238 disposed therein, and
each of the wellbores may have an electrode 232 disposed therein
and in electrical communication with the solution 238, as
previously described.
[0052] In other embodiments, any of the wellbores may be formed
with perforations (not shown), which may be present in the casing
and/or the artificial formation 212. The perforations may allow
injection of brine or other fluids from the surface into the
artificial formation 212. As such, the electrodes 232 may also have
perforations disposed therein. Accordingly, fluid injection may
occur by the conveyance of pressurized fluid through a tube string
233, out the electrode perforations, and into the artificial
formation 212.
[0053] Although not illustrated, the wellbores 204, 206 and/or the
conduit 228 may be at least partially disposed within or through
the producing formation 110, such that the wellbores 204, 206
and/or conduit 228 are independently or simultaneously useable for
production of hydrocarbonaceous fluids 230, in addition to creation
of the electric field within the solution 238. Thus, a
non-producing artificial formation may be converted to a producing
artificial formation, if desired.
[0054] Referring now to FIG. 3, a side view of an alternate
embodiment of a system for enhanced recovery of hydrocarbonaceous
fluids is shown. System 300, which may be of similar construction
and/or configuration as the system of FIG. 1 or 2, may include a
surface production facility 302 that produces hydrocarbonaceous
fluids 330 from a producing formation 310 by way of a wellbore 308.
The producing formation 310 may be surrounded by one or more
non-producing formations, such as overburden 314, bed rock 316,
and/or other earthen material 318.
[0055] FIG. 3 depicts an artificial formation 312 formed adjacent
to the producing formation 310, which may be conditioned using
methods such as fracturing, acidizing, etc., that may facilitate
creation of the artificial formation 312. The artificial formation
312 may include various structures, such as, for example, at least
two wellbores 304, 306 and a conduit 328. The wellbores 304, 306
and/or the conduit 328 may have a solution 338 disposed therein,
the solution 338 including a pre-existing body of solution, or
provided using one or more pumps 320, as described previously. As
such, any of the wellbores 304, 306 may be useable to convey fluids
to or from the artificial formation 312.
[0056] FIG. 3 also depicts a third wellbore 326, which may be
drilled, at least partially, through the producing formation 310
and into the artificial formation 312. In one embodiment, the third
wellbore 326 may include a preexisting wellbore used to recover
hydrocarbonaceous fluids from the producing formation 310.
Accordingly, drilling operations may be used to extend the third
wellbore 326 beyond the producing formation 310, while preexisting
or additional cementing and/or casing may be used to selectively
isolate the third wellbore 326 from the producing formation 310.
Thus, the third wellbore 326 may be in fluid communication with the
artificial formation 312, isolated from the producing formation
310, or combinations thereof.
[0057] The wellbores 304, 306, 326 may each have an electrode 332
disposed therein, such that any of the electrodes 332 may extend at
least partially into the solution 338. It should be appreciated
that one or more of the electrodes may function as a cathode 334,
and one or more of the electrodes 332 may function as an anode 333,
the operation of which would be known to one of skill in the art.
The electrodes 332 may be operatively connected with a power source
324, such as a DC power source or an AC power source, which may be
located, for example, at the surface. In one embodiment, the power
source 324 may generate single-phase AC. In another embodiment, the
power source 324 may generate three-phase AC. The AC signal may be,
for example, rectangular, sinusoidal, sawtooth, etc.
[0058] The power source 324 may be used to create an electric field
through the use of an electric circuit created between the power
source 324, electrodes 332, and solution 338, and may include any
of the power sources previously described, but is not meant to be
limited. Gas may be produced in the artificial formation 312 by an
electrolysis process, which may generally be understood as a
process that uses an electric current to drive an otherwise
non-spontaneous chemical reaction in a medium that contains mobile
ions, such as an electrolyte. In this case, the medium may be the
solution 338, which may include, for example, salt water or
brine.
[0059] As such, the electrodes 332 may provide an electrical
interface between the power source 324 and the solution 338. In
this manner, the power source 324 may be configured to provide the
energy to achieve the electrolysis, the further details of which
would be understood by one of ordinary skill in the art.
Accordingly, generation of an electric field within the solution
338 may initiate a region of exothermic electrochemical reaction at
the electrodes 332, in the solution 338, in the artificial
formation 312, and combinations thereof.
[0060] The producing formation 310 may include earthen material
that has a porosity sufficient to maintain the hydrocarbonaceous
fluids 330 within the producing formation 310, while permitting gas
from the artificial formation 312 to permeate into the producing
formation so that the gas may solvently mix with hydrocarbonaceous
fluids 330. As such, generated gas is released from the solution
338 may permeate from the artificial formation 312 into the
producing formation 310.
[0061] For example, in a solution of brine, hydrogen gas may be
generated, as illustrated by Equation 1 below:
2NaCl+2H.sub.2O.fwdarw.2NaOH+H.sub.2Cl.sub.2 [1]
[0062] As hydrogen gas is generated, hydrogen molecules, as a
result of the molecules' small size and inherent properties, may
permeate through the artificial formation, the producing formation,
and into the hydrocarbonaceous fluids. Permeation of hydrogen
molecules, or another similar gas, into the hydrocarbonaceous
fluids, may decrease the viscosity of the hydrocarbonaceous fluids
and increase pressure within the producing formation 310 to enhance
and/or enable production of the hydrocarbonaceous fluids. If
necessary, the artificial formation 312 may be maintained at a
selected pressure to facilitate permeation of the gas into the
producing formation 310.
[0063] Any components of the system, including the producing and
non-producing formations, may be configured with monitoring and
sensor capability (not shown), such that the recovery and/or
overall operation of the system may be measured, as would be known
to one of skill in the art. As such, the system may be optimized as
a result of system measurements and analysis thereof. The
optimization may include select adjustment of system variables,
such as the electric field generated by the power source. For
example, the electric field may be adjusted by changing at least
one of a current, a voltage, a frequency, and combinations thereof.
Other methods of optimization are possible in view of the
embodiments described herein.
[0064] Because the reaction is exothermic, an additional
synergistic effect of the reaction may include dissipation of heat
into the formation that further reduces the viscosity of the
formation fluids, and further increases pressure in the formation,
due to the additional volume of the gas at the heated temperature.
The increased volume of the formation fluids may also "break out"
hydrocarbonaceous fluids from formation matrix, whereby the fluids
may flow more readily toward the producing wellbore. As a result of
increased pressure and reduced viscosity, the hydrocarbonaceous
fluids may flow more readily toward the producing wellbore 308, and
the fluids may be easier and therefore cheaper to recover to the
surface.
[0065] Referring briefly to FIGS. 4A, 4B, 4C, 4D, 4E, and 4F
multiple partial downward views of various embodiments of systems
useable to enhance recovery of hydrocarbonaceous fluids, according
to embodiments of the present disclosure, are shown. FIG. 4A shows
a system 400, which may include various features and components
previously described but not shown, that may be used to produce
hydrocarbonaceous fluids 430 from a producing formation 410 by way
of a wellbore. The producing formation 410 may be surrounded by
non-producing formations, such as an overburden, bed rock, and/or
other earthen material (not shown).
[0066] As may be seen, there may be a plurality of wellbores
disposed within or external of the producing formation 410. In the
embodiment depicted, an artificial formation may be formed that
includes a first wellbore 404 in fluid communication with a second
wellbore 406. Fluid communication between the wellbores 404, 406
may be provided, for example, by conduit 428. Additional wellbores
may be provided, such as, for example, a wellbore 426, that is part
of the system 400, but is not in fluid communication with other
wellbores 404, 406; however, it should be understood that another
conduit (not shown) may be drilled to connect the wellbore 426 with
other wellbores 404, 406 and the conduit 428, as desired.
[0067] The wellbores 404, 406, and/or the conduit 428 may have a
solution disposed therein, and any of the wellbores that are part
of the artificial formation may be used to convey fluids into or
from the artificial formation. The wellbores 404, 406, may be
configured with an electrode (132, FIG. 1A, 1B) disposed therein.
As previously described, the electrodes may be used in conjunction
with the solution (138, FIG. 1A, 1B) to carry out an electrolysis
process.
[0068] FIGS. 4B-4F together illustrate operational variants of
system 400. FIG. 4B shows each of the wellbores 404, 406, and 426
in fluid communication. The artificial formation is shown including
a first conduit 428 formed, at least partially, under the producing
formation 410. Alternatively, or in addition, there may be a second
conduit 412 and a third conduit 413 formed, at least partially,
under the producing formation 410.
[0069] Although not illustrated here, the location of the bottom of
any of the wellbores and/or conduits may be as previously
described. For example, the bottom of the wellbores 404, 406, 426,
etc., may fully reside within the producing formation 410.
Similarly, conduit 428 may also fully reside within the producing
formation 410. In one embodiment, conduit 428 may be a
substantially horizontally drilled wellbore. FIG. 4D illustrates
wellbores 404, 406, and 426, as well as conduits 428, 412, and 413,
disposed within the producing formation 410. Alternatively, the
wellbores and connecting conduits may define an artificial
formation, which in one embodiment, may reside within, but are
fluidly isolated from, the producing formation 410.
[0070] FIG. 4C analogously illustrates an embodiment of the system
400. Specifically, the system 400 is shown including wellbores 404,
426 disposed external of the producing formation 410, and a
wellbore 406 disposed, at least partially, through the producing
formation 410. In an embodiment, wellbore 406 disposed at least
partially through the producing formation 410 may include a
previously producing wellbore. In a further embodiment, wellbore
406 may be simultaneously or sequentially used to produce the
hydrocarbonaceous fluids 430.
[0071] FIG. 4E further illustrates an embodiment of the system 400
that includes a fourth wellbore 429 provided in fluid communication
with the other wellbores 404, 406, 426 via a conduit 415. FIG. 4F
depicts an alternate embodiment of system 400 whereby wellbores and
conduits may be in separately isolated fluid communication. For
example, wellbores 404 and 406 may be in fluid communication as a
result of conduit 428, whereas wellbores 404a and 406a are
separately connected with each other by conduit 413.
[0072] It should be understood that the system 400 is not limited
to any specific number or configuration of wellbores and/or
electrodes 432. Any number of wellbores may be configured in fluid
communication or fluid isolation with or from other wellbores, as
desired. Additionally, the configurations depicted are possible
within the producing formation, or the configurations are possible
within a non-producing formation that is adjacent and external to
the producing formation, or combinations thereof.
[0073] Referring to FIG. 5A, a flow chart illustrating an
embodiment of a method for enhanced recovery of hydrocarbonaceous
fluids according to embodiments of the present disclosure, is
shown. As previously described, there may be a producing formation
that has a number of producing wellbores used for the recovery of
hydrocarbonaceous fluids from the formation. To enhance recovery of
the producing formation, an artificial formation may be created
adjacent to the producing formation.
[0074] The artificial formation may include a number of man-made or
machined components, such as a plurality of wellbores and
directionally drilled flow paths. Step 510 includes connecting at
least two of the plurality of wellbores together in fluid
communication with at least one of the flow paths. In some
embodiments, at least one of the flow paths may be substantially
horizontal. In other embodiments, there may be a plurality of
wellbores formed and/or connected in a triangulated pattern. Thus,
there may be fluid communication between at least three
non-producing wellbores.
[0075] A solution may pre-exist within the artificial formation, or
solution may be provided thereto, as shown by step 520. Thus, the
method may include providing a surface solution to any of the
wellbores and/or flow paths within the artificial formation. The
method may further include steps 530 and 540, which provide for
generating an electrical field within the flow path, thereby
causing an electrochemical reaction to produce a gas from the
solution. In one embodiment, the solution may be an electrolyte,
such as brine. In another embodiment, the solution may help conduct
electricity between any of the plurality of electrodes.
[0076] After producing the gas from the solution, the gas may
permeate out from the artificial formation, and into the producing
formation. Once the gas enters the producing formation, the gas may
be solvent to and/or mix with the hydrocarbonaceous fluids, as
indicated by step 550. Accordingly, the production of gas may
increase pressures within any part of the artificial formation, the
producing formation, or combinations thereof, thereby enhancing
recovery of the hydrocarbonaceous fluids.
[0077] The electrical field, and hence the electrochemical
reaction, may occur as a result of a power source operably
connected to a plurality electrodes. In other embodiments, the
power source may be an AC source that provides alternating current
to the solution. The power source may provide, for example, a
voltage of predetermined magnitude, for example, up to several
thousand volts. Once the power source is activated, a current flow
of, for example, one thousand amperes may flow between electrodes.
In an embodiment, the current may flow between the electrodes via a
medium disposed in the artificial formation. In a further
embodiment, the medium may be brine, and application of the
electrical field applied to the brine may produce hydrogen gas.
[0078] Referring to FIG. 5B, a flow chart illustrating multiple
steps of an alternate method for tertiary recovery of
hydrocarbonaceous fluids according to embodiments of the present
disclosure, is shown. The method may include step 610 of creating
an artificial subterranean formation at least partially underneath
a non-artificial producing formation, step 620 reacting a solution
disposed in the artificial formation to form a gas, and step 630
permeating the gas into the producing formation, such that the
permeated gas in the producing formation increases pressure within
the producing formation.
[0079] In an embodiment, the artificial subterranean formation may
include three wellbores in fluid communication, such that a
triangulated wellbore pattern may be formed. Each of the three
wellbores may include electrodes disposed therein to provide
polarization to the solution. In another embodiment, the artificial
subterranean formation may include a plurality of wellbores, with
at least two of the plurality of wellbores in fluid communication
as a result of a horizontally drilled conduit formed directly
underneath a natural producing formation.
[0080] Solution in the artificial formation may react to produce a
gas as a result of an electrolysis process created by an electric
field generated within the artificial subterranean formation. In
one embodiment, the solution may be brine, and the produced gas may
be hydrogen. However, the solution and produced gas are not meant
to be limited, and there may be other solutions that produce other
gases that are capable of permeating from the artificial formation
into the producing formation. Step 640 provides for mixing the gas
with hydrocarbonaceous fluids disposed in the natural producing
formation, thereby enhancing recovery of the hydrocarbonaceous
fluid.
[0081] The mixing of hydrogen gas into the hydrocarbonaceous fluids
may advantageously increase the producing formation pressure, and
may advantageously help release hydrocarbonaceous fluids from the
formation matrix. Accordingly, gas may beneficially mix with the
fluids thereby reducing the viscosity of the fluids. Production of
gases within a producing formation may advantageously provide
energy within the formation to repressure the formation if the
natural energy is no longer adequate to overcome the resistive
forces.
[0082] The electrochemical reaction of the present disclosure may
advantageously occur within and/or outside the producing formation,
such that the reaction does not depend on constituent elements
within the producing formation. Accordingly, systems and methods of
the present disclosure have no dependence on any formation
properties. There may beneficially include measurement
configurations for the select optimization of systems and methods
described herein.
[0083] Embodiments disclosed herein may provide systems and methods
for establishing an electrical field in a subsurface formation, and
establishing in response to the electrical field, a zone of
electrochemical activity that may result in an electrochemical
reaction that increases the formation pressure, reduces the
viscosity of any hydrocarbonaceous fluids in the formation, and
enhances recovery of the hydrocarbonaceous fluids.
[0084] While the present disclosure has been described with respect
to a limited number of embodiments, those skilled in the art having
benefit of the present disclosure will appreciate that other
embodiments may be devised which do not depart from the scope of
the disclosure described herein. Accordingly, the scope of the
disclosure should be limited only by the claims appended
hereto.
* * * * *